From the past, with cataract surgery and the like, a method has been used for which the intracapsular crystalline lens is extracted through an incision provided in ocular tissue such as the cornea (sclera) or anterior capsule of the lens or the like, and after removal, an intraocular lens substituted for that crystalline lens is inserted into the eye using that incision, and arranged within the capsule.
With this intraocular lens surgical operation method, there has been used an intraocular lens insertion device as noted in Patent Document 1 (Published Unexamined Japanese Patent Application No. JP-A-2003-70829) and Patent Document 2 (Published Unexamined Japanese Patent Application No. JP-A-2004-351196). With these intraocular lens insertion devices, the insertion tube part provided at the tip of the device main unit is made to be inserted and enter into the eye through the eye incision, and in a state with the intraocular lens deformed to be smaller within the device main unit, it is made to be extruded into the eye from the tip opening of the insertion tube part. Then, the intraocular lens is arranged within the capsule by the intraocular lens which was extruded into the eye expanding by its own restoration force within the capsule. If this kind of intraocular lens insertion device is used, it is possible to keep the incision small, making it possible to reduce the trouble required for the surgical operation and also possible to reduce the occurrence of postoperative astigmatism and the risk of infection.
As described above, with the intraocular lens insertion device, by the intraocular lens set on a stage provided in the device main unit being moved by the plunger while being pushed toward the insertion tube part, the intraocular lens is made to be extruded into the eye from the insertion tube part tip opening. It is typical for the intraocular lens to be set on a stage in a state with a pair of haptics formed projecting on the optical portion in a state extended facing front and back in the movement direction of the intraocular lens by the plunger. Because of that, when extruding the intraocular lens using the plunger, first, the plunger contacts the haptic (back haptic) extending in the backward movement direction of the intraocular lens, and by the force applied from the plunger being transmitted to the optical portion via the back haptic, the entire intraocular lens is moved toward the insertion tube part.
However, when the entire intraocular lens is pushed via the back haptic and extruded forward to the insertion tube part by the plunger, there is the risk of the back haptic coming off from the plunger pressing surface (tip surface). It is hard for a practitioner to know whether the back haptic has come off the plunger pressing surface. Because of that, by continuing to press the pressing member as is, the back haptic that has come off the plunger pressing surface becomes sandwiched between the inner periphery surface of the insertion tube part that gradually becomes smaller toward the extrusion front and the plunger outer peripheral surface. This sandwiching may cause damage to the back haptic as well as the risk of the plunger pushing operation resistance becoming large, causing problems with the intraocular lens procedure.
In Published Unexamined Japanese Patent Application No. JP-A-2009-18009 (Patent Document 3), proposed is an intraocular lens insertion device with a constitution for which a groove opened at the outer peripheral surface is formed on the tip part of a plunger, and the back haptic that has come off the plunger tip surface is housed inside that groove. However, it is difficult to reliably house the back haptic inside the narrow width groove, and also continue to maintain that housed state throughout the intraocular lens extrusion operation. Also, the back haptic that has come off from the groove formed on the plunger outer peripheral surface is wrapped around the plunger outer peripheral surface. This causes the problem that it can enter between the plunger outer peripheral surface and the insertion tube part inner periphery surface, so it was not a satisfactory product.